Method and device for treating the surfaces of component bores

ABSTRACT

The invention relates to a method for treating the surfaces (I) of bore holes in components, in particular for treating the running paths (I) of cylinder bores (B1, B2, B3, B4) in engine blocks (M) by means of a laser beam (X) which is directed by deviation optics (100) to the surface (I) to be treated; and to a device suitable for the same treatment purpose which allows the treatment of surfaces of component bore holes with increased precision and with improved efficiency at low expenditure. The method according to the invention is characterised in that during the treatment process the component (M) is rotated around an axis of rotation aligned parallel to the longitudinal axis of the bore hole to be treated, with the deviation optics (100) being stationary; and in that unbalanced masses occurring during rotation of the component (M) are balanced by balancing masses (21, 22).

The invention relates to a method and a device for treating the surfacesof bore holes in components, in particular for treating the runningpaths of cylinder bores in engine blocks by means of a laser beam whichis directed by deviation optics to the surface to be treated.

For surface treatment of heavily loaded surfaces of bore holes, inparticular for treatment of the running surfaces of cylinder bores ofinternal combustion engines, devices are used which heat up the runningpath to be treated by laser beams with a high energy density. Theincidence of the laser beam into the bore hole is coaxial to the axis ofrotation of the deviation optics, said axis of rotation coinciding withthe longitudinal axis of the bore hole. By means of a rotating mirror,the laser beam is deflected in the deviation optics and projectedtowards the surface to be treated.

In the case of the known treatment stations, due to their small size andlight weight, the deviation optics can be rotated without any problemsat high rotational speeds. Depending on the number of rotationscompleted, during treatment the deviation optics are insertedprogressively deeper into the bore hole via suitable linear drives,until treatment is completed. Following this, the deviation optics arewithdrawn from the bore hole and moved to the subsequently to be treatedbore hole by a further linear drive.

The advantage of the known treatment station is due to the light weightof its deviation optics. This makes it possible when treating bore holesurfaces, to move only small masses. Accordingly, only low centrifugalforces have to be overcome during treatment of the surfaces.Furthermore, the high rotational speed of the deviation optics resultsin effective and even treatment of the bore hole surfaces. The lightweight also enables easy advance with little expenditure of energy, ofthe deviation optic to the bore hole to be treated next. Due to thesetwo known advantages of the known treatment stations, the said stationscan be compact and low cost and can thus be produced more economically.

However, practical use has shown that the known treatment stations canonly be operated at low efficiency. Due to the confined space and thenecessity of arranging the deviation mirror of the deviation optics onits axis of rotation, only a fraction of the laser beam actually reachesthe surface to be treated.

Apart from the above-mentioned state of the art known from practicalexperience, Patent Abstracts of Japan, C-50, 1981, vol. 5, no. 54, JP56-5923 A discloses a device wherein for heat treatment of the surfacesof bore holes in cylindrical components by means of a laser beam, whichis directed to the surface to be treated by way of deviation optics,during treatment the cylindrical component is rotated around an axis ofrotation parallel to the longitudinal axis of the bore hole to betreated, with the deviation optics being stationary.

It is the object of the invention to provide a method and a device whichwith little expenditure allows the treatment of surfaces of componentbore holes with increased precision and with improved efficiency.Concerning a method of the type described in the introduction, thisobject is met in that during the treatment process, the component isrotated around an axis of rotation aligned parallel to the longitudinalaxis of the bore hole to be treated, with the deviation optics beingstationary; and in that unbalanced masses occurring during rotation ofthe component are balanced by balancing masses. Preferably the axis ofrotation of the component should coincide with the axis of rotation ofthe bore hole to be treated.

This object is also met by a device for treating the surfaces of boreholes in components, in particular for treating the running paths ofcylinder bores in engine blocks, by means of a laser beam, comprisingdeviation optics insertable into the bore holes to be treated, fordeviating the laser beam onto the surface to be treated; a turntabledrive for rotating the component around an axis of rotation arrangedparallel to the longitudinal axis of the respective bore hole to betreated and arranged within the bore aperture, and with at least onebalancing mass which are able to be coupled to the turntable drive forbalancing unbalanced masses which occur during rotation of thecomponent.

According to the invention it is proposed that the component as a wholebe rotated around an axis of rotation which is arranged in the bore holeto be treated, with the deviation optics for the laser being stationary.At the same time, the unbalanced masses caused by rotating thecomponents are balanced by suitably arranged balancing masses. In thisway quiet, troublefree rotation of the component during treatment isinsured in spite of the significant centrifugal forces occurring duringrotation of the component.

In spite of the increased expenditure of a device according to theinvention, for the drive of the component; in spite of the necessity ofhigh drive forces in particular when treating larger heavier componentssuch as engine blocks; and in spite of the significant centrifugalforces to be balanced when rotating heavy components, surprisingly,considerably improved results are achieved in comparison to theconventional treatment method. This is possible in that the deviationoptics which are stationary during treatment, are decoupled from thevibrations of the rotational movement of the component, so that thelaser beam can be projected with high precision onto the surface to betreated, unaffected by housing oscillations.

The precision of projection of the laser beam onto the surface to betreated can be additionally improved in that the centre of the laserbeam projected into the bore hole is spaced apart from the longitudinalaxis of the bore hole. It is thus possible to arrange the deviationmirror of the deviation optics at a greater distance to the surface tobe treated. As a result of the associated increase in focal length, animprovement in projection accuracy of the laser beam is achieved.

In particular when treating components of complex shape, it isfavourable if a control device is provided which, depending on theunbalanced mass occurring during rotation of a component, issues controlsignals to regulating devices for changing the position and/or theweight of the balancing mass. With such a control device, unbalancedmasses during rotation of the component can be balanced automatically.

Balancing of the unbalanced mass can also occur in an economic way inthat, forced by mechanical coupling, a change in position of thecomponent results in a corresponding change in the position of thebalancing mass for balancing the unbalanced mass caused by the change inposition of the component. A device according to the invention arrangedin such a way ensures that any change in position of the component whichresults in unbalanced mass, results in a corresponding change in theposition of the balancing mass so as to balance the unbalanced mass.Such mechanical coupling of the movement can be achieved simply in thatthe component is attachable to a first slide movable along a firstlinear movement path; that the balancing mass is movable along a secondmovement path aligned parallel to the first movement path; and that themovement of the first slide is coupled to the movement of the balancingmass by way of a rack and pinion gear. Such an embodiment of theinvention is particularly advantageous if the bore holes to be treated,such as for example the cylinder bores of an engine block, are arrangedin line. In this context it is also favourable if there are at least twobalancing masses with in each instance a movement path for one of thebalancing masses being arranged in the region of one side of the slide,and the movement path of the other balancing mass being arranged on theopposite side of the slide. In this way, several balancing masses ofsmall dimensions and small individual weights can be attached in aspace-saving way to the device according to the invention.

A practical embodiment of a device according to the invention, whichembodiment operates at high precision, is characterised in that theslide carrying the component is arranged on a turntable driven by a mainturntable drive; that the slide is coupled to a drive shaft by means ofa gear which converts the rotary movement of said drive shaft coupled tothe main turntable drive to a linear movement of the slide; and thatthere is an intermediate gear by means of which by introducing anadditional turntable drive movement, a difference in rotational speedbetween the turntable and the drive shaft can be generated. A deviceconfigured in this way makes it possible to adjust the slide carryingthe component along a linear movement path while the component isrotating. No interruption of the rotation for repositioning thecomponent after treatment of a bore hole is required, consequently nowork time is lost for braking and restarting the turntable.

It is favourable if the deviation optics comprise a housing insertableinto the bore hole into which the laser beam is projected so as to beoffset in relation to the longitudinal axis; and comprise a deviationmirror arranged in the housing in the path of incidence of the laserbeam, said deviation mirror deflecting said laser beam to an exitaperture provided in the case surface of the housing. Such an embodimentof the deviation optics makes it possible to precisely project the laserbeam onto the surface to be treated at maximum focal length.

The invention provides a significant advantage in that due to theposition of the laser beam being offset in relation to the longitudinalaxis of the bore hole to be treated, it is possible in a simple way, inthe region of the deviation optics, to provide adequate space forremoval by suction of the gasses resulting from treatment of thesurfaces of the bore hole. In this way, the deviation optics can be keptclean and any negative influence on the treatment result caused by thesettling of previously removed particles can be prevented.

Below, the invention is illustrated in more detail by means of a drawingshowing one embodiment. The following are shown in diagrammatic view:

FIG. 1 a lateral view of a device for treating the running surfaces ofcylinder bores in an engine block;

FIG. 2 a top view of a device according to FIG. 1;

FIG. 3 a frontal, part-sectional view of the device according to FIGS. 1and 2;

FIG. 4 a partial sectional longitudinal view of the deviation optics,intended for use in the device according to FIGS. 1 to 3, inserted intoa bore hole; and

FIG. 5 a top view of the deviation optics shown in FIG. 4.

The device 1 shown in FIGS. 1 to 3 comprises a mount 2 in which a hollowshaft 4 carrying a turntable 3 is retained. A drive shaft 5 runs onbearings inside the hollow shaft 5, with the ends 5a, b of said shaftprotruding from the upper end of the hollow shaft 4 associated with theturntable 3, or the lower end 4b of the hollow shaft 4. At the upper end5a of the drive shaft 5 there is a conical gear wheel 6, and at thelower end 5b of said drive shaft there is a pulley 7 attached.

The conical gear wheel 6 attached to the drive shaft 5 interacts with aconical gear wheel 9 attached to a threaded spindle 8 aligned at a rightangle to the drive shaft 5. The end section of the threaded spindle 8associated with the drive shaft 5 runs on a bearing 10 supported by theturntable 3. A slide 12 is coupled to the threaded spindle 8 by way of athreaded piece 11.

The slide 12 is slidably retained by parallel straight guide rails 13,14 attached to the turntable 3. Associated with the respective guiderails 13, 14, there are toothed racks 15, 16 on the underside of theslide 12. The teeth of said toothed racks 15, 16 point towards thenearest edge of the slide 12. Respective cogs 17, 18 running on bearingson the turntable 3 interact with the toothed racks 15, 16. In addition arespective toothed rack interacts with the cogs 17, 18, said toothedracks being formed by the lateral edge associated with the slide 12 of afurther slide 19, 20 arranged parallel to the slide 12. Each of theslides 19, 20 carries a balancing mass 21, 22, whose weight correspondsto half the weight of a motor M borne by the slide 12. By way of thetoothed racks 15, 16, the cogs 17, 18 and the toothed racks of the slide19, 20, each movement of the slide 12 in one direction causes arespective repositioning of the slides 19, 20 in the opposite direction.

On its top, the slide 12 comprises rollers 23 arranged axially parallelto each other by way of which a transport pallet 24 carrying the engineblock M is slidable onto the slide 12 by means of a loading andunloading device 25. In the position shown in the figures, the engineblock M is fixed to the slide 12 together with the transport pallet 24.

On the lower end of the hollow shaft 2 there is also a pulley 26attached, with a belt 27 in place. This belt 27 connects the hollowshaft 4 with a pulley 28 which is attached to the lower shaft end of anintermediate shaft 29 retained in the mount 2. At its upper end, theintermediate shaft 29 carries two pulleys 30, 31. The intermediate shaft29 is connected to a main drive 32 by way of the upper pulley 31.

Via the other pulley 30, by means of a belt 34, a pulley 35 attached toan input shaft of an intermediate gear 33 is connected to theintermediate shaft 29. A belt 36 connects a pulley 37 borne by an outputshaft of the intermediate gear 33 with the pulley 7 of the drive shaft 5so that the drive shaft 5 is connected to the main drive 32 by way ofthe intermediate gear 33 and the intermediate shaft 29.

By means of an additional drive motor 38 interacting with theintermediate gear 33, an additional rotary movement can be introduced tothe drive train for the drive shaft 5, said drive train being formed bythe belt 35, the pulley 34, the intermediate drive 33, the pulley 37 andthe belt 36. This rotational movement can be in the same direction asthe direction of rotation of the turntable 3 or it can be in theopposite direction.

The diameters of the pulleys 7, 26, 28, 30, 31, 34, 36 are matched toeach other in such a way that with the additional drive motor 38switched off, the shaft 5 rotates at the same speed as the turntable 3borne by the hollow shaft 4. If the additional drive motor 38 introducesa rotary movement, in the same direction as that of the turntable, tothe drive train for the drive shaft 5, said drive shaft 5 rotates athigher speed than that of turntable 3. This results in the threadedspindle 8 starting to rotate at a speed corresponding to the differencein rotational speed between the turntable 3 and the drive shaft 5. Inthis way, the slide 12 is moved along the guide rails 13, 14 on a linearmovement track. By contrast if by way of the intermediate drive 33 arotation opposite the rotational direction of the turntable 3 isintroduced into the drive train for the drive shaft 5, then said driveshaft 5 rotates correspondingly more slowly than the turntable 3 so thatthe threaded spindle 8 starts turning in the opposite direction.Accordingly, the slide 12 is moved in the opposite direction to thedirection previously described.

The deviation optics 100 shown in FIGS. 4 and 5 comprise a cylindrical,pot-shaped housing 101. The diameter of the housing is smaller than thediameter of the bore holes B1, B2, B3, B4 to be treated, of the engineblock M. Thus with the deviation optics 100 inserted into the bore holecoaxially, there is an annular gap R between the interior surface I andthe case surface 102 of the housing 101.

The deviation optics 100 are fixed to the free end of a boom 50 of aregulating device 51 operating in vertical direction, with the length ofsaid regulating device being such that the longitudinal axis Lg of thedeviation optics 100 is aligned coaxially to the axis of rotation LD ofthe turntable 3.

In the area of the transition between its case surface 102 and itsbottom, the housing 101 comprises a recess into which a mirror insert103 of prismatic cross-section is inserted. The mirror surface 104 ofthe mirror insert 103 associated with the inner side of the housing 101is aligned at an angle of 45° to the longitudinal axis Lg of the housing101, with the centre of the mirror surface 104 being arranged so as tobe offset, in respect to the longitudinal axis Lg, by a quarter of thehousing diameter.

Within the housing 101 there is a channel 105 with a diameter largerthan the diameter of the mirror surface 104, said channel being arrangedconcentrically to said mirror surface 104 and above it. The entranceaperture 109 of the channel 105 is located on the upper rim 106 of thehousing 101.

The case surface 102 of the housing 101 comprises an aperture 107. Theaperture 107 is arranged concentrically to an imaginary straight linearranged in a plane normally aligned along the longitudinal axis Lgintersecting the centre of the mirror surface and, seen from above,meeting the mirror surface 104 at a right angle.

For treatment of the interior surface I of one of the bore holes B1, B2,B3, B4 arranged one behind the other of the motor M, while the turntableis rotating and while the motor M is rotating with the turntable 3, thedeviation optics 100 are lowered, by means of the regulating device 51into the bore hole B1 to be treated, up to the starting position of thesection to be treated of the interior surface I. Subsequently, a device80 for generating a laser beam X is switched on. The laser beam X whichat first is aligned at a right angle to the longitudinal axis Lg of thehousing 101 is deflected via a suitable deviation mirror 81 such that itreaches the housing 101 as a beam aligned parallel to the longitudinalaxis Lg of the deviation optics 100 but at a distance to said deviationoptics 100. Its centre Z is concentrically aligned in respect to themouth of the channel 105 of the deviation optics 100. The laser beam Xreaching the housing of the deviation optics 100 through the channel 105is projected onto the mirror surface 104 which deflects it at a rightangle to the aperture 107 of the housing 101. The laser beam X leavesthe deviation optics 100 by way of this aperture 107 and reaches therotating interior surface I to be treated.

The heating up of the interior surface I caused by the laser beam Xresults in evaporation of particles adhering to the interior surface.The resulting gases are removed by suction by way of the annular gap Rformed between the housing 101 of the deviation optics 100 and theinterior surface I of the bore hole B1, and additionally by way of thecross sections which are not taken up by the channel 105 and its walls.

Depending on the progress of treatment, the deviation optics 100 arelowered into the bore hole B1 until the end of the section of theinterior surface I to be treated is reached. Now the deviation optics100 are removed from the bore hole B1. While the turntable 3 continuesto rotate in the way described above, subsequently the slide 12 is movedin a linear direction by introducing an additional drive movement intothe drive train for the drive shaft 5, until the longitudinal axis ofthe subsequently to be treated bore hole B2 is aligned coaxially to thelongitudinal axis Lg of the deviation optics 100. Due to the coupling,caused by the toothed racks 15, 16, the cogs 17, 18, and the toothedracks of the slides 19, 20, of the movements of the slide 12 carryingthe motor M with the slide s 19, 20 carrying the balancing masses 21,22, said balancing masses 21, 22 are always in a position in which thebalancing masses 21, 22 balance the unbalanced mass caused by therotating motor M.

What is claimed is:
 1. A method for treating surfaces of bore holes incomponents by means of a laser beam which is directed by deviationoptics to the surface to be treated,wherein during the treatmentprocess, the component is rotated around an axis of rotation alignedparallel to the longitudinal axis of the bore hole to be treated,wherein the deviation optics are stationary, and wherein unbalancedmasses occurring during rotation of the component are balanced bybalancing masses.
 2. The method of claim 1 wherein the holes are runningpaths of cylinder bores in engine blocks.
 3. The method of claim 1wherein the axis of rotation of the component coincides with thelongitudinal axis of the bore holes to be treated.
 4. The method ofclaim 1 wherein the center of the laser beam projected into the boreholes is spaced apart from the longitudinal axis of the bore holes.
 5. Adevice for treating surfaces of bore holes in components by means of alaser beam comprising:deviation optics insertable into the bore holes tobe treated for deviating the laser beam onto the surface to be treated,a turntable drive for rotating the component around an axis of rotationarranged parallel to the longitudinal axis of the respective bore holesto be treated and arranged within the bore holes, and at least onebalancing mass which is able to be coupled to the turntable drive forbalancing unbalanced masses which occur during rotation of thecomponent.
 6. The device of claim 5 wherein the holes are running pathsof cylinder bores in engine blocks.
 7. The device of claim 5 wherein acontrol device issues control signals to regulating devices for changingat least one of the position and weight of the balancing mass dependingon the unbalanced mass occurring during rotation of a component.
 8. Thedevice of claim 5 wherein the component is attachable to a first slidemovable along a first linear movement path,wherein the balancing mass ismovable along a second movement path aligned parallel to the firstmovement path, and wherein the movement of the first slide is coupled tothe movement of the balancing mass by means of a rack and pinion gear.9. The device of claim 8 wherein there are at least two balancingmasses.
 10. The device of claim 9 wherein in each instance one movementpath for one of the balancing masses is arranged in the region of oneside of the slide and the movement path of the other balancing mass isarranged on the opposite side of the slide.
 11. The device of claim 8wherein the slide carrying the component is arranged on a turntabledriven by a main turntable drive,wherein the slide is coupled to a driveshaft by means of a gear which converts the rotary movement of the driveshaft coupled to the main turntable drive to a linear movement of theslide, and wherein there is an intermediate gear which introduces anadditional turntable drive movement so as to generate a difference inrotational speed between the turntable and the drive shaft.
 12. Thedevice of claim 8 wherein the axis of rotation of the componentcoincides with the longitudinal axis of the bore holes of the component.13. The device of claim 12 wherein the deviation optics furthercomprise:a housing insertable into the bore hole into which the laserbeam is projected so as to be offset in relation to the longitudinalaxis, and a deviation mirror arranged in the housing in the path ofincidence of the laser beam which deflects the laser beam to an exitaperture in the housing.